When she settled down a bit, the breathless co-host explained that Donnie Wahlberg had proposed over the weekend with a little help from her 11-year-old son, Evan Asher, whom she had with her then-husband John Mallory Asher.

"Donnie went into the other room and out came Evan with a card that said, 'Will,' and he handed it to me and I didn't know what was going on yet," McCarthy recounted.

"And then Evan ran away and Evan came back with a card that said 'You.' And then he ran away and I knew what was happening and I just started crying. And then Evan came back with a card that said 'marry; but spelled wrong -- it said 'M-A-R-Y' -- and then the last time Donnie came out with Evan, and Donnie's shirt said 'Me?' with a question mark holding the ring."

Now tearful, she continued, "and he got down on his knee and he said, 'Will you marry me?,' and I, of course, said yes and in that moment Evan yelled, 'I have another dad,' and it just made all of us cry. I feel like the luckiest girl in the world. He's so wonderful."

And that's when the "Blue Bloods" actor appeared onstage to surprise his new fiancée.

Though the pair haven't set a wedding date yet, McCarthy said they're thinking of tying the knot in August, "or maybe stretching it out a year."

She also thanked fans via social media, posting a photo on Instagram of herself canoodling with her man.

"Thank you for all of the sweet wishes. @donniewahlberg and I are grateful and blessed. #love #bhlove," she wrote, showing off her sparkler in the photo.

McCarthy and Wahlberg met on the set of her old VH1 talk show, "The Jenny McCarthy Show," and started dating soon after a joint appearance on Bravo's "Watch What Happens Live," according to E! News. They took their relationship public in July 2013 and confirmed reports when they appeared together at a "Dancing With the Stars" charity event in August.

It will be a second wedding for McCarthy, who was hitched to Asher from 1999 to 2005 and made headlines earlier this year for her flip-flopping stance on child vaccinations. She dated comedian Jim Carrey after her divorce, before splitting with him in 2010. It's also a second marriage for Wahlberg, who has two sons from his previous union to Kim Fey. That pair split in 2008.